The US-led coalition fighting ISIS confirmed on Wednesday that three personnel had been killed in a rocket attack on a military camp in Iraq and that about 12 additional personnel were wounded.

In a statement, the coalition said that approximately 18 Katyusha rockets struck the base. Camp Taji is an Iraqi base that hosts Coalition personnel for training and advising missions.

"The attack is under investigation by the Coalition and Iraqi Security Forces," the statement said.

The US leads an international coalition - comprised of dozens of countries and thousands of soldiers - formed in Iraq in 2014 to confront ISIS, an extremist group that Baghdad declared defeated in late 2017.

Previous rocket attacks targeting US soldiers, diplomats and facilities in Iraq in recent months have killed one US contractor and an Iraqi soldier.

None of the attacks have been claimed, but Washington accuses pro-Iran factions of being responsible.

Two days after the death of an American in rockets fired on an Iraqi military base in Kirkuk at the end of last year, the US army hit five bases in Iraq and Syria used by the pro-Iran armed faction Kata’ib Hezbollah.